Studying different languages increases our understanding of how humans communicate and their different cultures. However, almost 80% of the people in the world speak only 1% of its languages.  Every 14 days a language dies. By 2100, half of the more than 7, 000 languages spoken on Earth today may disappear.

    Throughout history, the languages of dominant(统治的)groups have spread while the languages of native cultures have become extinct. This happens because of government language policies, or because the dominant language becomes more useful in everyday life. Furthermore, many endangered languages aren't written down. When the last speakers of a language die and their language becomes extinct, their stories, songs, and other important information are lost, too.

    Central South America has some of the world's most endangered languages. The Kallawaya people speak a secret language that has details of thousands of medical plants. Today, fewer than 100 people speak it. In Central and Eastern Siberia, many Siberian languages now have only a few elderly speakers. Yuchi, which may be unrelated to any other language in the world, is one of the many native languages used in Oklahoma, the U.S.A. It is disappearing rapidly. In 2010, only five elderly people could speak this language.

    Luckily, native cultures around the world are using modern technology to help keep their endangered languages and cultures alive. Communities are creating dictionaries and libraries by using pictures, video, and audio to record the traditions of the last speakers of their language. If the young people don't speak and understand the words and stories of their ancestors(祖先), the language will die.

    And when the language dies, part of the culture dies, too.

    Birthdays are celebrated all over the world. Some traditions are rather similar from one country to another: candles, cakes and birthday wishes. But there are also different ways to celebrate birthdays.

    Here are a few:

    Argentina (阿根廷): In Argentina, as in many Latin American countries, one of the most important birthday parties is a girl's fifteenth. When girls turn 15, they have a huge party and dance first with their fathers, and then the boys at the part.

    China: The birthday child receives presents from the parents. Friends and family members are invited to dinner, and noodles are served to wish the birthday child a long life.

    Denmark (丹麦): A flag is flown outside a window to show that someone who lives in that house is celebrating the birthday. Presents are placed around the child's bed while he is sleeping so he can see them immediately when he wakes up.

    Holland (荷兰): The birthday child receives an especially large present. The family also put flowers or balloons on the birthday child's chair to make it beautiful.

    India: Usually Indian children wear white to school. However, the birthday child wears colored clothes to school and gives out chocolates to everyone in the class. His /Her best friend helps do this.

    Japan: The birthday child wears new clothes to mark the special time. Certain birthdays are more important than others and these are celebrated with a visit to the shrine (神殿). These are the third and seventh birthdays for girls and the fifth for boys.

Where would you like to stay when you go on a vacation? What kind of hotel would you like to choose? Different people have different ideas. In fact, there are all kinds of special places to stay when you go on a vacation. There are hotels, motels, youth hostels, B&Bs (bed-and-breakfast), home stays, and more. Each is for a different kind of people. If you travel by car, a motel is good for you. You can park your car outside your room. A youth hostel is good for young backpackers (背包客). A B&Bs might be best for couples (夫妻) or anybody who doesn't like being noisy.

    For people who like reading, the library hotel in New York is a must-see. Each of the hotel's 60 rooms is full of books. In fact the hotel has over 6, 000 books in all. If history is your thing, the 9th floor is for you. If you are interested in math and science, you can stay on the 5th floor. Artists will feel at home on the 7th floor. The Poetry Garden is on the 14th floor, and there is a cozy sofa in it. You can sit on the sofa and enjoy reading a good book or relax outside in the Poetry Garden.